Many hotels and motels have been equipped with toilets in which the vertical water inlet pipe to the toilet tank comes up through a chamber which is separate from the water chamber of the tank. In one form of such toilets this separate chamber is physically outside the toilet tank. In another form this separate chamber is formed by a cylindrical housing extending up within the toilet tank but sealed from it in water-tight fashion at the top and bottom. In both forms the upper end of the vertical water inlet pipe was connected by a horizontal pipe to a side inlet opening in a toilet tank water inlet valve operated by a ballcock. These side-inlet ballcock-operated valves are not available any longer so that when such a valve no longer functions properly it cannot be easily replaced with a ballcock-operated water inlet valve having a bottom inlet opening that is not aligned with the horizontal pipe extending from the upper end of the vertical water inlet pipe.